I've been using YaCy for a long time.(ver.1.72 to 1.83)
Today, I tried the update it to ver. 1.90!
After pushing restart button, YaCy does'nt start up correctly.
So I tried to use it in the initial state.(Re-install YaCy)
However, YaCy can't still run... at all.

Steps To Reproduce

Download YaCy from the official site, and extract it.
Then execute 'startYACY.sh'.

java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
at net.yacy.kelondro.blob.Tables.getTablenames(Tables.java:264)
at net.yacy.kelondro.blob.Tables.iterator(Tables.java:241)
at net.yacy.data.ymark.YMarkTables.buildIndex(YMarkTables.java:138)
at net.yacy.data.ymark.YMarkTables.<init>(YMarkTables.java:111)
at net.yacy.data.WorkTables.<init>(WorkTables.java:95)
at net.yacy.search.Switchboard.<init>(Switchboard.java:421)
at net.yacy.yacy.startup(yacy.java:218)
at net.yacy.yacy.main(yacy.java:726)

E 2016/07/06 21:02:03 ConcurrentLog java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
at net.yacy.kelondro.blob.Tables.getTablenames(Tables.java:264)
at net.yacy.kelondro.blob.Tables.iterator(Tables.java:241)
at net.yacy.data.ymark.YMarkTables.buildIndex(YMarkTables.java:138)
at net.yacy.data.ymark.YMarkTables.<init>(YMarkTables.java:111)
at net.yacy.data.WorkTables.<init>(WorkTables.java:95)
at net.yacy.search.Switchboard.<init>(Switchboard.java:421)
at net.yacy.yacy.startup(yacy.java:218)
at net.yacy.yacy.main(yacy.java:726)